1899] MICROSCOPICAL JOURNAL. 219 



done the slightest scratch will show on the photograph, 

 which is very delicate, and will not stand much rough 

 usage. The shellac preparation used by photographers 

 to pour over tin types will be found best for the purpose, 

 as it dries very quickly. 



Cut the cards on which the photos are mounted to the 

 standard size, 3 inches by 1 inch, taking great caro to en- 

 sure that the background is exactly centred on the card. 



2. Take a slip of dry and well-seasoned bay wood or 

 mahogany, 3 inches long, 1 inch wide, and 1-16 inch thick 

 (thinner or thicker if required). Glue over the strip on 

 each side a piece of manila paper of good quality, using 

 liquid glue, and dry under a flat weight. 



When dry cut out the centre of the wooden slip, leav- 

 ing a strip ^ inch wide on each side, and 5 16 inch at each 

 end. Then smooth down all the roughnesses with tine 

 glass-paper, and blacken all over with lamp-black in al- 

 cohol. Add sufficient shellac to the alcohol to make the 

 lamp-black adhere to the cell, but not enough to make a 

 gloss. 



3. Glue the photographed bottom to the wooden cell 

 with liquid glue, and dry under a flat weight. 



4. Place a thin glass slip, 3 inches by 1, of best quali- 

 ty, with ground edges, on top of the cell. 



5. Take a slip of manilla paper, about 3 inches long 

 by 2^ inches wide, moisten with a sponge, wrap it round 

 the cell and glass slip, and glue the edges on the back of 

 the photographed bottom. Be very careful that no glue 

 touches the glass-cover. All the manilla paper used in 

 the preparation of the slide must be dampened but not 

 soaked ; the damp paper stretches and works better. 



6. Take a strip of manilla paper, 1 inch by about 6^ 

 inches long, damp and glue it, and paste over the last 

 strip. This strip will go right round the long diameter 

 of the slide. No glue must be allowed to touch the glass 

 cover where the paper goes over it at the ends. 



